The 3.9 is a terrible engine! I had a 2000 Dakota with one and I got very tired of it. No power below 2500 RPM and lots of vibraton above 3500 RPM. The best mileage I ever got on a tank of gas was 17 and that was while being very careful. Most of the time it was about 15 with an empty bed. With dirt bikes in the back the added wind resistance meant it would just barely pull 5th gear on the highway. What a thirsty, vibrating, dog! Both the 318 and its derivitive, the 3.9 are famous for poor fuel economy. When Chrysler cut two cylinders off the 318 they created the vibration problem that all V6s have. But they didn't add a balance shaft or some other "fix" like Ford did with their 3.8.

I don't think you'll ever break a 3.9 but you will get tired of it's bad babits.

Wetspirit